Portable light box and heat developing unit



Sept. 16, 1969 c. A. DONNELLY, JR., ET AL 3,457,470

PORTABLE LIGHT BOX AND HEAT DEVELOPING UNIT 2 Sheets-Sheet 1 Filed May 8, 1967 RM m M O N wa Sept. 16, 1969 c DQNNELLY JR ET AL 3,467,470

PORTABLE LIGHT BOX AND HEAT DEVELOPING UNIT Filed May 8, 1967 2 Sheets-Sheet 2 //v1//vr0/?: 074K154 wr /Year R. (SEEN/4190M GHFF .ON

Mew/v A. 5704.4

United States Patent 3,467,470 PORTABLE LIGHT BOX AND HEAT DEVELOPING UNIT Charles A. Donnelly, Jr., South St. Paul, Bernard W. Galfron, Minneapolis, and Marvin A. Stoll, St. Paul, Minn., assignors to Minnesota Mining and Manufacturing Company, St, Paul, Minn., a corporation of Delaware Filed May 8, 1967, Ser. No. 636,933 Int. Cl. G03b 27/72 US. Cl. 355-115 ABSTRACT OF THE DISCLOSURE A self-contained portable copier having a removable folding light box which fits over a mangle heat-developing unit and timer unit all enclosed in a folding case. In one side of the case is located a hinged exposure pressureplate over which the light box is placed during the exposure process.

This invention relates to portable copy-machines.

In US. Patent No. 3,234,868 there is described a portable copying apparatus in which is combined a base containing a removable support pad and pressure plate and having aflixed thereto a heating platen, and a domed cover containing a light source and fitting over the platen and against the base. The device is useful in making copies of graphic originals using sensitive intermediate and copysheet materials and copying processes all as described in US. Patent No. 3,094,417.

In one aspect the present invention likewise provides a portable copying apparatus including light-exposure and heat-development stations and useful in making copies of graphic originals with the materials and by the procedures described in said Patent No. 3,094,417, but having a number of advantages over the apparatus of Patent No. 3,234,868, as will be made apparent in the following description taken in conjunction with the appended drawing, in which FIGURE 1 is a view in perspective of the portable copying apparatus closed for transporting,

FIGURE 2 is a view in section of the apparatus of FIGURE 1 in open position taken along section 2-2,

FIGURE 3 is an end elevation of the exposure unit opened for use and partly cut away,

FIGURE 4 is a side elevation of the apparatus of FIG- URE 2, portions being cut away,

FIGURE 5 is a top plan view showing the heat-development unit, and

FIGURE 6 is a top plan view showing the exposure unit in closed position.

In the drawing the several components are identified by the same numbers in the various figures, which however are not all drawn to the same scale.

In one convenient form the apparatus 10 comprises a folding case having external dimensions of approximately 16 x 14 x 5 inches and having much the appearance of an attach case or small suitcase. The case comprises two lids 11 and 12 hingedly attached to a base 14 forming the heat development unit, the lids in closed position as shown in FIGURE 1 enclosing both the latter unit and the closed exposure unit 13. Handle assembly 17 forms the top of the exposure unit and also provides a carrying handle for the copy-machine when closed for transportmg.

Within the lid 11 there is contained a soft fiat resiliently compressible support 18 and a light-transmissive flat pressure-cover 19 hingedly affixed to the lid along the outer edge as at hinge 34. The opposite lid 12 includes a compartment 20 for storage of a supply of sensitive intermedi- 6 Claims.

3,467,470 Patented Sept. 16, 1969 ate and copy-sheet materials. The two lids fit snugly together when in closed position, being held by suitable snaps or locks 35.

The heater unit 14, forming the base of the copier, contains a floating heater shoe 23 biased by a spring 36 against a soft-surfaced roller 21 which is rotated by an electric motor 22. The surface of the roller is desirably coated with fibrous flock, forming a soft but springy or resilient and very uniform pressure-applying and paperadvancing surface. A counting device or timer 24 is driven from the shaft of the roller at the end opposite the motor and is visible through a circular first opening in the top panel 37 of the unit 14 as shown in FIGURE 5. A rectangular second opening in the top of the unit 14 provides access to the roller 21. Along one side of the second opening the top 37 is extended upwardly to form a paperguiding ledge 38. Space is provided beneath the heater 23 and accessible from the lid 12 for storage of an electric cord and plug with which to connect the heater and motor to a source of power. A suitable socket, not shown, may desirably be provided at one end of the base 14 for interconnection with the exposure unit next to be described, and shallow grooves 39 along the longitudinal outer edges of the top 37 are provided to receive the edges of said unit.

The exposure unit 13 includes a top handle and lamp assembly supported on a folding reflector unit having rectangular side panels 15 and truncated triangular end panels 16. Each end panel is divided by fold lines into two outer triangular sections 29, 31 and a central inverted triangular section 30, the latter carrying a rotatable clamp 27 which in the horizontal position shown in FIGURE 3 holds the three segments in the same plane. When the clamp 27 is turned to the vertical position shown in FIG- URE 4 the end panels may be folded inwardly, drawing the side panels into parallelism with each other so that their lower edges may be fitted within the grooves 39 of the base 14 as indicated in FIGURE 2. End braces 28 depending from the ends of the top 17 prevent excessive outward movement of the end panels 16 upon opening of the exposure unit.

The top 17 is in the form of a box-like trough having raised sides and ends 40, rounded bosses 41, and a central raised platform 42 forming a retainer for a folding handle 32. A lamp socket 35 is suspended centrally from within the lower portion of the top member 17 and carries a light source 26. A pushbutton 33 near one end of the platform 42 is connected to the socket 35 and the two are connected to a suitable cord and plug for connection to a source of electric power, preferably through the socket provided for the purpose in the base 14. When not in use, the cord is wound around the bosses 41 and within the trough-like top.

The upper outer edges of the lids 11 and 12 are centrally cut away to fit snugly against the sides and ends of the handle-retaining platform 42 when the apparatus is closed, as is seen from FIGURE 1.

To make a copy, the case is opened, the exposure unit is lifted from the heater unit and is expanded and locked in the position shown in FIGURE 3, and the exposure and heater units are connected to a source of electric power. The graphic original of which a copy is desired is placed against the support pad 18 with the printed surface exposed and is covered with a sheet of light-sensitive intermediate. The cover 19 is brought down onto the composite and the exposure unit fitted against the cover and held down under moderate pressure while the push-button 33 is pressed to activate the lamp 26. Duration of exposure is measured by reference to the timer 24 in accordance with requirements. By this reflex exposure the portions of the intermediate sheet overlying the unprinted background areas of the original are completely desensitized, whereas only partial desensitization occurs at image areas.

The exposed intermediate is next removed and placed against a sensitive copy-sheet,"and the two-sheet composite is then inserted into the heater unit. Insertion is facilitated by placing the leading edge of the composite against the face of the ledge 38 from whence the sheets slip easily between the roller 21 and the heated shoe 23, being advanced by the motion of the roller and ejected at the opposite side of the rectangular opening. The heating action promotes an image-forming reaction at the image areas on the copy-sheet, and the intermediate sheet is then stripped away and discarded.

An important feature of the apparatus described is its simplicity and the resultant economy in manufacture, combined with its compactness, ready portability, and simplicity of operation. The apparatus is entirely self-contained. The essential components, i.e. the pressure-pad, exposure unit, and heater unit, are available for use with a minimum of operation. The components are simple and easily obtainable. As a particular example, the prefrred light source is an incandescent filament bulb such as an ordinary house lighting bulb or a Photoflood bulb, and the reflector panels 15, 16 are formed of 0.3 mil aluminum foil and 43-point (.043 inch) chipboard laminate.

High intensity and uniformity of illumination over the entire exposure area is obtained with the simplified exposure unit here described. Maximum reflection is an obvious requirement if light sources of low or moderate intensity, such as those hereinabove mentioned, are to be successfully employed; but mirror surfaces such as polished aluminum plate or silvered glass produce localized highlighting, whereas surfaces coated with light-ditfusing reflective paints are found to require unduly prolonged exposure times and to give blotchy light-patterns and nonuniform copies. Surprisingly, the minutely irregular but specularly reflective polished aluminum surface obtained in the pressure-roll lamination of thin aluminum foil to chipboard provides both a high degree and a high uniformity of illumination at the exposure area using the single centrally supported light source as herein described.

What is claimed is as follows:

1. A self-contained portable copying apparatus for making copies of original documents by a process involving exposing an original to light through an intermediate sheet in pressure-contact therewith, and heating the thus exposed intermediate in pressure-contact with a receptor copy-sheet, said apparatus including: a pad and plate assembly comprising a resilient support pad and a light-transmissive pressureplate for holding an original and intermediate therebetween in condition for exposure; a folding light-box, having an open bottom fitting over the exposure area of said plate and pad, for uniformly illuminating said area and comprising reflective side and flolding end panels foldably attached to a rigid top carrying a light source, and switch means for actuating said source; and a mangle having a resilient-surface roller revolving against a heated curved shoe for heating said intermediate and copy-sheet under pressure-contact andincluding timing mechanism associated with said roller for use in determining the time of a said exposure; said mangle serving as a base for said apparatus and having hingedlyattached thereto two opposing lids cooperating to provide an enclosure for said mangle, light-box, and pad and plate assembly.

2. The apparatus of claim 1 wherein said support pad is supported against the inner fiat surface of a said lid and the pressure-plate is hingedly supported within said lid and against said pad.

3. The apparatus of claim 1 wherein said rigid top includes at its outer surface a handle memberextending beyond said enclosure and serving as a handle both for said apparatus and for said light-box.

4. The apparatus of claim 1 wherein said light-box panels have a minutely irregular specularly reflective surface as obtainedby pressure-roll lamination of thin aluminum foil to cardboard.

5. The apparatus of claim 1 wherein said resilientsurface roller is rotated by a constant-speed motor and in turn rotates a separate timing mechanism.

6. The apparatus of claim 1 wherein the width of said apparatus closed for transporting is not more than about one-half the width of said exposure area.

References Cited UNITED STATES PATENTS 6/1963 Lewis 355115 X 2/1966 Appeldorn et a1. 355-115 US. Cl. SX.R. 250; 96-28 

